How odd that i started a thread based on the that very valve and shower head.
Anyway, even though mine witll be placed over our bath, i'm actually putting the valve below the shower head rail. I've worked out enough room without anything being strained and the valves are at the right height to allow the rail to be so far above it but not have the shower head protrude over the top of the shower screen. In your case top of cubicle.

With the rail above the valves just centre them both on the width of the wall they're going on.

Err...where are you valve pipes going if you are fixing to a solid wall?

Thank you for your response.
I'm thinking of putting the vertical rail 475mm from the wall, and the centre of the mixer valve 800mm away. The bottom fixing of the rail and the mixer valve I thought to put 1200mm up from the shower tray floor - that's the highest the rail can go, with the shower head touching the (sloping) ceiling.

the valves are at the right height

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What height is that ?

With the rail above the valves just centre them both on the width of the wall they're going on.

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It's an offset quadrant, so half-way along might be a bit tight against the curved doors.

This shower is in the en-suite. I'm going to cut chases in the brickwork for the pipes. Luckily they come through the wall from behind a vanity unit in the bathroom.

Roin, have you figoure out how the valve connects to the pipe?
The instructions on mine show that the 's' connector screws into an 'adaptor' that's already in the wall, but this adaptor isn't supplied and i've no idea what it's supposed to be.

Roin, have you figoure out how the valve connects to the pipe?
The instructions on mine show that the 's' connector screws into an 'adaptor' that's already in the wall, but this adaptor isn't supplied and i've no idea what it's supposed to be.

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I shall terminate each supply pipe with a compression wall-plate elbow (http://www.screwfix.com/p/wall-plate-elbow-15mm-x/92934) which has a foot to screw to the wall, which will have to be dug out big enough and deep enough (with the bottom of the hole smooth enough ! The horizontal part of the elbow is 1/2" iron (flush with the tiling) into which the S connector will fit later - with lots of PTFE tape - after the tiling is complete.. All then wrapped in denso tape and mortared up - though I *hate* the very idea of burying a compression joint !

I've got a diamond core drill big enough to cut holes in the tiles to fit over the end of the elbow, with some "wriggle room".

I bought some female wallplate elbows too, but ideally i need female couplers as they have to go through 12.5mm of plasterboard plus about 7-8mm or so of tile/adhesive.
The pipes are in the cavity wall going straight through the middle of some batons for stability.

I guess you may have to amble into your local friendly plumbing shop and seek their advice

You may have to end up with something like a 15mm to 22mm reducer, then a bit of 22mm pipe, then a 22mm compression to 3/4" female wall-plate elbow, with a 3/4" male to 1/2" female reducer on the end...

I guess you may have to amble into your local friendly plumbing shop and seek their advice

You may have to end up with something like a 15mm to 22mm reducer, then a bit of 22mm pipe, then a 22mm compression to 3/4" female wall-plate elbow, with a 3/4" male to 1/2" female reducer on the end...

Good luck !

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Lol, what? Pretty sure all i need is a 3/4 female coupler, compressed at one end to the 15mm horizontal pipe, then the body of it goes through the thickness of the backboard board and tile so that the valve can screw into the female end.
Not too hard, its just that the wallplate elbow won't work cos my pipes are situated further back into the cavity.